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A super-eruption of an Italian volcano that may have played a
major role in the Neanderthals' fate was apparently even larger
than thought, new research suggests.

For the new study, scientists investigated the
Campi Flegrei caldera volcano in southern Italy. About 39,000
years ago, it experienced the
largest volcanic eruption that Europe has seen in the last
200,000 years. This super-eruption may have played a part in
wiping out or driving away Neanderthal and modern human
populations in the eastern Mediterranean.

To learn more about this outburst, scientists measured 115 sites
for the ash layer it laid down, known as Campanian Ignimbrite.
They next analyzed this data with a 3D ash-dispersal computer
model.

The researchers discovered the super-eruption behind the
Campanian Ignimbrite would have spewed 60 to 72 cubic miles (250
to 300 cubic kilometers) of ash across 1.4 million square miles
(3.7 million square km). This is twice to triple the previous
estimate of the volume of ash spouted by the eruption.

These findings, detailed online May 30 in the journal Geophysical
Research Letters, suggest the super-eruption would have spread up
to 990 million pounds (450 million kilograms) of poisonous sulfur
dioxide into the atmosphere. This air pollution would have cooled
the Northern Hemisphere, driving down temperatures by 1.8 to 3.6
degrees Fahrenheit (1 to 2 degrees Celsius) for two to three
years, enough to have severe effects on the environment. (For
comparison, the air pollutants generated by the
1991 eruption of Mount Pinatubo reduced global temperatures
by about 0.9 degrees Fahrenheit (0.5 degrees Celsius).

The researchers noted that the Campi Flegrei super-eruption took
place in what was already an especially cold, dry period in the
last Ice Age. "The eruption would have made conditions even worse
for the Neanderthal and modern human populations," researcher
Antonio Costa, a volcanologist at the University of Reading in
England and the Italian National Institute of Geophysics and
Volcanology in Naples, told OurAmazingPlanet.

Fluorine-laden ash from the eruption that later became
incorporated into plant matter eaten by these hominids could have
also potentially caused a condition known as fluorosis, which can
lead to eye, tooth and organ damage. In addition, sulfur dioxide,
fluorine and chlorine emissions from the volcano would have
generated intense acid rain downwind of the volcano.

The researchers plan to look at other super-eruptions, such as
the Toba outburst about 75,000 years ago, "which was much larger
than the Campanian Ignimbrite," Costa said. "We can also study
the
Yellowstone super-volcano."